{"id":935,"date":"2025-11-30T17:13:50","date_gmt":"2025-11-30T09:13:50","guid":{"rendered":"http:\/\/www.tgwttt.xyz\/?p=935"},"modified":"2025-11-30T17:13:51","modified_gmt":"2025-11-30T09:13:51","slug":"%e4%b8%80%e7%af%87%e6%96%87%e7%ab%a0%e5%b8%a6%e4%bd%a0%e5%bd%bb%e5%ba%95%e6%90%9e%e6%87%82mysql%e4%b8%ad%e7%9a%84%e4%ba%8b%e5%8a%a1%e6%9c%ba%e5%88%b6","status":"publish","type":"post","link":"https:\/\/www.tgwttt.xyz\/?p=935","title":{"rendered":"\u4e00\u7bc7\u6587\u7ae0\u5e26\u4f60\u5f7b\u5e95\u641e\u61c2MySQL\u4e2d\u7684\u4e8b\u52a1\u673a\u5236"},"content":{"rendered":"\n

\u5f15\u8a00\uff1a<\/strong><\/h2>\n\n\n\n
\"\"<\/figure>\n\n\n\n

\u5f53crud\u4e0d\u88ab\u63a7\u5236\u4f1a\u53d1\u751f\u4ec0\u4e48\u573a\u666f\uff1f\u4ee5\u6211\u4eec\u65e5\u5e38\u4e70\u7968\u768412306\u6765\u770b\uff0c\u5f53\u53ea\u5269\u4e00\u5f20\u7968\u7684\u65f6\u5019\uff0c\u4e24\u4e2a\u4eba\u540c\u65f6\u4e70\u7968\uff0c\u5982\u679c\u4e0d\u52a0\u4ee5\u63a7\u5236\u5c31\u4f1a\u51fa\u73b0\u7968\u6570\u4e3a\u8d1f\u7684\u73b0\u8c61\uff08\u5982\u4e0a\u56fe\uff09<\/p>\n\n\n\n

\n

\u8bd5\u60f3\u6570\u636e\u5e93\u64cd\u4f5c\u5fc5\u987b\u6709\u54ea\u4e9b\u7279\u6027\u624d\u80fd\u89e3\u51b3\u4e0a\u9762\u95ee\u9898\u5462<\/strong><\/p>\n\n\n\n

1. \u4e70\u7968\u7684\u8fc7\u7a0b\u5f97\u662f\u539f\u5b50\u7684\u5427<\/p>\n\n\n\n

2. \u4e70\u7968\u4e92\u76f8\u5e94\u8be5\u4e0d\u80fd\u5f71\u54cd\u5427<\/p>\n\n\n\n

3. \u4e70\u5b8c\u7968\u5e94\u8be5\u8981\u6c38\u4e45\u6709\u6548\u5427<\/p>\n\n\n\n

4. \u4e70\u524d\uff0c\u548c\u4e70\u540e\u90fd\u8981\u662f\u786e\u5b9a\u7684\u72b6\u6001\u5427<\/p>\n<\/div>\n\n\n\n

\u4e8b\u52a1<\/strong><\/h2>\n\n\n\n
\n

\u4ec0\u4e48\u662f\u4e8b\u52a1\uff1f<\/strong><\/p>\n\n\n\n

\u4e8b\u52a1<\/strong>\u00a0\u662f\u6307\u5728\u6570\u636e\u5e93\u4e2d\u6267\u884c\u7684\u4e00\u7ec4\u64cd\u4f5c\uff0c\u8fd9\u4e9b\u64cd\u4f5c\u8981\u4e48\u5168\u90e8\u6210\u529f\uff0c\u8981\u4e48\u5168\u90e8\u5931\u8d25\u3002\u4e8b\u52a1\u7684\u4e3b\u8981\u76ee\u7684\u662f\u786e\u4fdd\u6570\u636e\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u3002\u7b80\u5355\u6765\u8bf4\u4e8b\u52a1\u5c31\u662f\u4e00\u7ec4DML\u8bed\u8a00\u8981\u4e48\u540c\u65f6\u6210\u529f\u8981\u4e48\u540c\u65f6\u5931\u8d25\u3002<\/p>\n<\/div>\n\n\n\n

\n

\u4e8b\u52a1\u56db\u5927\u7279\u6027<\/strong><\/p>\n\n\n\n

\n

\u901a\u8fc7\u4e0a\u9762\u7684\u4f8b\u5b50\uff0c\u4e8b\u52a1\u7406\u5e94\u5177\u5907\u4ee5\u4e0b\u7279\u6027<\/p>\n\n\n\n

\u7b80\u79f0\u4e3a\u00a0ACID<\/strong>\uff1a\u539f\u5b50\u6027\u3001\u4e00\u81f4\u6027\u3001\u9694\u79bb\u6027\u548c\u6301\u4e45\u6027\u3002<\/p>\n<\/div>\n<\/div>\n\n\n\n

\n

\u539f\u5b50\u6027<\/strong>\uff1a\u4e00\u4e2a\u4e8b\u52a1\uff08transaction\uff09\u4e2d\u7684\u6240\u6709\u64cd\u4f5c\uff0c\u8981\u4e48\u5168\u90e8\u5b8c\u6210\uff0c\u8981\u4e48\u5168\u90e8\u4e0d\u5b8c\u6210\uff0c\u4e0d\u4f1a\u7ed3\u675f\u5728\u4e2d\u95f4\u67d0\u4e2a\u73af\u8282\u3002\u4e8b\u52a1\u5728\u6267\u884c\u8fc7\u7a0b\u4e2d\u53d1\u751f\u9519\u8bef\uff0c\u4f1a\u88ab\u56de\u6eda\uff08Rollback\uff09\u5230\u4e8b\u52a1\u5f00\u59cb\u524d\u7684\u72b6\u6001\uff0c\u5c31\u50cf\u8fd9\u4e2a\u4e8b\u52a1\u4ece\u6765\u6ca1\u6709\u6267\u884c\u8fc7\u4e00\u6837\u3002<\/p>\n\n\n\n

\u4e00\u81f4\u6027<\/strong>\uff1a\u5728\u4e8b\u52a1\u5f00\u59cb\u4e4b\u524d\u548c\u4e8b\u52a1\u7ed3\u675f\u4ee5\u540e\uff0c\u6570\u636e\u5e93\u7684\u5b8c\u6574\u6027\u6ca1\u6709\u88ab\u7834\u574f\u3002\u8fd9\u8868\u793a\u5199\u5165\u7684\u8d44\u6599\u5fc5\u987b\u5b8c\u5168\u7b26\u5408\u6240\u6709\u7684\u9884\u8bbe\u89c4\u5219\uff0c\u8fd9\u5305\u542b\u8d44\u6599\u7684\u7cbe\u786e\u5ea6\u3001\u4e32\u8054\u6027\u4ee5\u53ca\u540e\u7eed\u6570\u636e\u5e93\u53ef\u4ee5\u81ea\u53d1\u6027\u5730\u5b8c\u6210\u9884\u5b9a\u7684\u5de5\u4f5c\u3002<\/p>\n\n\n\n

\u9694\u79bb\u6027<\/strong>\uff1a\u6570\u636e\u5e93\u5141\u8bb8\u591a\u4e2a\u5e76\u53d1\u4e8b\u52a1\u540c\u65f6\u5bf9\u5176\u6570\u636e\u8fdb\u884c\u8bfb\u5199\u548c\u4fee\u6539\u7684\u80fd\u529b\uff0c\u9694\u79bb\u6027\u53ef\u4ee5\u9632\u6b62\u591a\u4e2a\u4e8b\u52a1\u5e76\u53d1\u6267\u884c\u65f6\u7531\u4e8e\u4ea4\u53c9\u6267\u884c\u800c\u5bfc\u81f4\u6570\u636e\u7684\u4e0d\u4e00\u81f4\u3002\u4e8b\u52a1\u9694\u79bb\u5206\u4e3a\u4e0d\u540c\u7ea7\u522b\uff0c\u5305\u62ec\u8bfb\u672a\u63d0\u4ea4\uff08 Read uncommitted \uff09\u3001\u8bfb\u63d0\u4ea4\uff08 read committed \uff09\u3001\u53ef\u91cd\u590d\u8bfb\uff08 repeatable read \uff09\u548c\u4e32\u884c\u5316\uff08 Serializable \uff09<\/p>\n\n\n\n

\u6301\u4e45\u6027<\/strong>\uff1a\u4e8b\u52a1\u5904\u7406\u7ed3\u675f\u540e\uff0c\u5bf9\u6570\u636e\u7684\u4fee\u6539\u5c31\u662f\u6c38\u4e45\u7684\uff0c\u5373\u4fbf\u7cfb\u7edf\u6545\u969c\u4e5f\u4e0d\u4f1a\u4e22\u5931\u3002<\/p>\n<\/div>\n\n\n\n

\n

\u4e3a\u4ec0\u4e48\u4f1a\u51fa\u73b0\u4e8b\u52a1?<\/strong><\/p>\n\n\n\n

\u4e8b\u52a1\u88ab MySQL \u7f16\u5199\u8005\u8bbe\u8ba1\u51fa\u6765,\u672c\u8d28\u662f\u4e3a\u4e86\u5f53\u5e94\u7528\u7a0b\u5e8f\u8bbf\u95ee\u6570\u636e\u5e93\u7684\u65f6\u5019,\u4e8b\u52a1\u80fd\u591f\u7b80\u5316\u6211\u4eec\u7684\u7f16\u7a0b\u6a21\u578b,\u4e0d\u9700\u8981\u6211\u4eec\u53bb\u8003\u8651\u5404\u79cd\u5404\u6837\u7684\u6f5c\u5728\u9519\u8bef\u548c\u5e76\u53d1\u95ee\u9898.\u53ef\u4ee5\u60f3\u4e00\u4e0b\u5f53\u6211\u4eec\u4f7f\u7528\u4e8b\u52a1\u65f6,\u8981\u4e48\u63d0\u4ea4,\u8981\u4e48\u56de\u6eda,\u6211\u4eec\u4e0d\u4f1a\u53bb\u8003\u8651\u7f51\u7edc\u5f02\u5e38\u4e86,\u670d\u52a1\u5668\u5b95\u673a\u4e86,\u540c\u65f6\u66f4\u6539\u4e00\u4e2a\u6570\u636e\u600e\u4e48\u529e\u5bf9\u5427?\u56e0\u6b64\u4e8b\u52a1\u672c\u8d28\u4e0a\u662f\u4e3a\u4e86\u5e94\u7528\u5c42\u670d\u52a1\u7684.\u800c\u4e0d\u662f\u4f34\u968f\u7740\u6570\u636e\u5e93\u7cfb\u7edf\u5929\u751f\u5c31\u6709\u7684.<\/p>\n<\/div>\n\n\n\n

\u4e8b\u52a1\u64cd\u4f5c<\/strong><\/p>\n\n\n\n

\n
\n
\n

1.\u5728mysql\u6570\u636e\u5e93\u4e2d\u53ea\u6709Innodb\u5f15\u64ce\u53ef\u4ee5\u4f7f\u7528\u4e8b\u52a1<\/p>\n\n\n\n

2.\u5728 MySQL \u4e2d\uff0c\u4e8b\u52a1\u53ef\u4ee5\u5206\u4e3a\u9690\u5f0f\u4e8b\u52a1\u548c\u663e\u5f0f\u4e8b\u52a1\u3002\u9690\u5f0f\u4e8b\u52a1\u662f\u6307 MySQL \u81ea\u52a8\u7ba1\u7406\u4e8b\u52a1\u7684\u5f00\u542f\u548c\u63d0\u4ea4\uff0c\u800c\u663e\u5f0f\u4e8b\u52a1\u5219\u9700\u8981\u5f00\u53d1\u8005\u624b\u52a8\u63a7\u5236\u3002<\/p>\n<\/div>\n\n\n\n

3.\u9690\u5f0f\u4e8b\u52a1\u5728\u6267\u884c\u00a0INSERT<\/em>\u3001UPDATE<\/em>\u3001DELETE<\/em>\u00a0\u7b49\u64cd\u4f5c\u65f6\uff0cMySQL \u4f1a\u81ea\u52a8\u5f00\u542f\u548c\u63d0\u4ea4\u4e8b\u52a1\u3002\u662f\u5426\u5f00\u542f\u9690\u5f0f\u4e8b\u52a1\u7531\u53d8\u91cf\u00a0autocommit<\/em>\u00a0\u63a7\u5236\u3002<\/p>\n<\/div>\n\n\n\n

\n

— \u67e5\u770b autocommit \u53d8\u91cf<\/strong>
SHOW VARIABLES LIKE ‘autocommit’;<\/p>\n\n\n\n

\"\"<\/figure>\n<\/div>\n<\/div>\n\n\n\n
\n

4.\u663e\u5f0f\u4e8b\u52a1\u9700\u8981\u624b\u52a8\u5f00\u542f\u3001\u63d0\u4ea4\u6216\u56de\u6eda\u3002\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4e24\u79cd\u65b9\u5f0f\uff1a<\/p>\n\n\n\n

SET autocommit=0; — \u5173\u95ed\u81ea\u52a8\u63d0\u4ea4
— \u6267\u884c\u4e8b\u52a1\u64cd\u4f5c
COMMIT; — \u63d0\u4ea4\u4e8b\u52a1
ROLLBACK; — \u56de\u6eda\u4e8b\u52a1<\/p>\n\n\n\n

\"\"<\/figure>\n<\/div>\n\n\n\n

START TRANSACTION; — \u5f00\u542f\u4e8b\u52a1
— \u6267\u884c\u4e8b\u52a1\u64cd\u4f5c
COMMIT; — \u63d0\u4ea4\u4e8b\u52a1
ROLLBACK; — \u56de\u6eda\u4e8b\u7269<\/p>\n\n\n\n

\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b<\/h2>\n\n\n\n
\n

1.MySQL\u670d\u52a1\u53ef\u80fd\u4f1a\u540c\u65f6\u88ab\u591a\u4e2a\u5ba2\u6237\u7aef\u8fdb\u7a0b(\u7ebf\u7a0b)\u8bbf\u95ee\uff0c\u8bbf\u95ee\u7684\u65b9\u5f0f\u4ee5\u4e8b\u52a1\u65b9\u5f0f\u8fdb\u884c<\/p>\n\n\n\n

2.\u4e00\u4e2a\u4e8b\u52a1\u53ef\u80fd\u7531\u591a\u6761SQL\u6784\u6210\uff0c\u4e5f\u5c31\u610f\u5473\u7740\uff0c\u4efb\u4f55\u4e00\u4e2a\u4e8b\u52a1\uff0c\u90fd\u6709\u6267\u884c\u524d\uff0c\u6267\u884c\u4e2d\uff0c\u6267\u884c\u540e\u7684\u9636\u6bb5\u3002\u800c\u6240\u8c13\u7684\u539f\u5b50\u6027\uff0c\u5176\u5b9e\u5c31\u662f\u8ba9\u7528\u6237\u5c42\uff0c\u8981\u4e48\u770b\u5230\u6267\u884c\u524d\uff0c\u8981\u4e48\u770b\u5230\u6267\u884c\u540e\u3002\u6267\u884c\u4e2d\u51fa\u73b0\u95ee\u9898\uff0c\u53ef\u4ee5\u968f\u65f6\u56de\u6eda\u3002\u6240\u4ee5\u5355\u4e2a\u4e8b\u52a1\uff0c\u5bf9\u7528\u6237\u8868\u73b0\u51fa\u6765\u7684\u7279\u6027\uff0c\u5c31\u662f\u539f\u5b50\u6027\u3002<\/p>\n\n\n\n

3.\u4f46\uff0c\u6bd5\u7adf\u6240\u6709\u4e8b\u52a1\u90fd\u8981\u6709\u4e2a\u6267\u884c\u8fc7\u7a0b\uff0c\u90a3\u4e48\u5728\u591a\u4e2a\u4e8b\u52a1\u5404\u81ea\u6267\u884c\u591a\u4e2aSQL\u7684\u65f6\u5019\uff0c\u5c31\u8fd8\u662f\u6709\u53ef\u80fd\u4f1a\u51fa\u73b0\u4e92\u76f8\u5f71\u54cd\u7684\u60c5\u51b5\u3002\u6bd4\u5982\uff1a\u591a\u4e2a\u4e8b\u52a1\u540c\u65f6\u8bbf\u95ee\u540c\u4e00\u5f20\u8868\uff0c\u751a\u81f3\u540c\u4e00\u884c\u6570\u636e\u3002<\/p>\n\n\n\n

4.\u5c31\u5982\u540c\u4f60\u5988\u5988\u7ed9\u4f60\u8bf4\uff1a\u4f60\u8981\u4e48\u522b\u5b66\uff0c\u8981\u5b66\u5c31\u5b66\u5230\u6700\u597d\u3002\u81f3\u4e8e\u4f60\u600e\u4e48\u5b66\uff0c\u4e2d\u95f4\u6709\u4ec0\u4e48\u56f0\u96be\uff0c\u4f60\u5988\u5988\u4e0d\u5173\u5fc3\u3002\u90a3\u4e48\u4f60\u7684\u5b66\u4e60\uff0c\u5bf9\u4f60\u5988\u5988\u6765\u8bb2\uff0c\u5c31\u662f\u539f\u5b50\u7684\u3002\u90a3\u4e48\u4f60\u5b66\u4e60\u8fc7\u7a0b\u4e2d\uff0c\u5f88\u5bb9\u6613\u53d7\u522b\u4eba\u5e72\u6270\uff0c\u6b64\u65f6\uff0c\u5c31\u9700\u8981\u5c06\u4f60\u7684\u5b66\u4e60\u9694\u79bb\u5f00\uff0c\u4fdd\u8bc1\u4f60\u7684\u5b66\u4e60\u73af\u5883\u662f\u5065\u5eb7\u7684\u3002<\/p>\n\n\n\n

5.\u6570\u636e\u5e93\u4e2d\uff0c\u4e3a\u4e86\u4fdd\u8bc1\u4e8b\u52a1\u6267\u884c\u8fc7\u7a0b\u4e2d\u5c3d\u91cf\u4e0d\u53d7\u5e72\u6270\uff0c\u5c31\u6709\u4e86\u4e00\u4e2a\u91cd\u8981\u7279\u5f81\uff1a\u9694\u79bb\u6027<\/p>\n\n\n\n

6.\u6570\u636e\u5e93\u4e2d\uff0c\u5141\u8bb8\u4e8b\u52a1\u53d7\u4e0d\u540c\u7a0b\u5ea6\u7684\u5e72\u6270\uff0c\u5c31\u6709\u4e86\u4e00\u79cd\u91cd\u8981\u7279\u5f81\uff1a\u9694\u79bb\u7ea7\u522b<\/p>\n<\/div>\n\n\n\n

\u9694\u79bb\u7ea7\u522b\u8bfb\u672a\u63d0\u4ea4\u3010Read Uncommitted\u3011<\/strong>\uff1a \u5728\u8be5\u9694\u79bb\u7ea7\u522b\uff0c\u6240\u6709\u7684\u4e8b\u52a1\u90fd\u53ef\u4ee5\u770b\u5230\u5176\u4ed6\u4e8b\u52a1\u6ca1\u6709\u63d0\u4ea4\u7684\u6267\u884c\u7ed3\u679c\u3002\uff08\u5b9e\u9645\u751f\u4ea7\u4e2d\u4e0d\u53ef\u80fd\u4f7f\u7528\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u7684\uff09\uff0c\u4f46\u662f\u76f8\u5f53\u4e8e\u6ca1\u6709\u4efb\u4f55\u9694\u79bb\u6027\uff0c\u4e5f\u4f1a\u6709\u5f88\u591a\u5e76\u53d1\u95ee\u9898\uff0c\u5982\u810f\u8bfb\uff0c\u5e7b\u8bfb\uff0c\u4e0d\u53ef\u91cd\u590d\u8bfb\u7b49\uff0c\u6211\u4eec\u4e0a\u9762\u4e3a\u4e86\u505a\u5b9e\u9a8c\u65b9\u4fbf\uff0c\u7528\u7684\u5c31\u662f\u8fd9\u4e2a\u9694\u79bb\u6027\u3002<\/p>\n\n\n\n

\u8bfb\u63d0\u4ea4\u3010Read Committed\u3011 <\/strong>\uff1a\u8be5\u9694\u79bb\u7ea7\u522b\u662f\u5927\u591a\u6570\u6570\u636e\u5e93\u7684\u9ed8\u8ba4\u7684\u9694\u79bb\u7ea7\u522b\uff08\u4e0d\u662f MySQL \u9ed8\u8ba4\u7684\uff09\u3002\u5b83\u6ee1\u8db3\u4e86\u9694\u79bb\u7684\u7b80\u5355\u5b9a\u4e49:\u4e00\u4e2a\u4e8b\u52a1\u53ea\u80fd\u770b\u5230\u5176\u4ed6\u7684\u5df2\u7ecf\u63d0\u4ea4\u7684\u4e8b\u52a1\u6240\u505a\u7684\u6539\u53d8\u3002\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u4f1a\u5f15\u8d77\u4e0d\u53ef\u91cd\u590d\u8bfb\uff0c\u5373\u4e00\u4e2a\u4e8b\u52a1\u6267\u884c\u65f6\uff0c\u5982\u679c\u591a\u6b21 select\uff0c \u53ef\u80fd\u5f97\u5230\u4e0d\u540c\u7684\u7ed3\u679c\u3002<\/p>\n\n\n\n

\u53ef\u91cd\u590d\u8bfb\u3010Repeatable Read\u3011<\/strong>\uff1a \u8fd9\u662f MySQL \u9ed8\u8ba4\u7684\u9694\u79bb\u7ea7\u522b\uff0c\u5b83\u786e\u4fdd\u540c\u4e00\u4e2a\u4e8b\u52a1\uff0c\u5728\u6267\u884c\u4e2d\uff0c\u591a\u6b21\u8bfb\u53d6\u64cd\u4f5c\u6570\u636e\u65f6\uff0c\u4f1a\u770b\u5230\u540c\u6837\u7684\u6570\u636e\u884c\u3002\u4f46\u662f\u4f1a\u6709\u5e7b\u8bfb\u95ee\u9898\u3002<\/p>\n\n\n\n

\u4e32\u884c\u5316\u3010Serializable\u3011<\/strong>: \u8fd9\u662f\u4e8b\u52a1\u7684\u6700\u9ad8\u9694\u79bb\u7ea7\u522b\uff0c\u5b83\u901a\u8fc7\u5f3a\u5236\u4e8b\u52a1\u6392\u5e8f\uff0c\u4f7f\u4e4b\u4e0d\u53ef\u80fd\u76f8\u4e92\u51b2\u7a81\uff0c\u4ece\u800c\u89e3\u51b3\u4e86\u5e7b\u8bfb\u7684\u95ee\u9898\u3002\u5b83\u5728\u6bcf\u4e2a\u8bfb\u7684\u6570\u636e\u884c\u4e0a\u9762\u52a0\u4e0a\u5171\u4eab\u9501\uff0c\u3002\u4f46\u662f\u53ef\u80fd\u4f1a\u5bfc\u81f4\u8d85\u65f6\u548c\u9501\u7ade\u4e89\uff08\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u592a\u6781\u7aef\uff0c\u5b9e\u9645\u751f\u4ea7\u57fa\u672c\u4e0d\u4f7f\u7528\uff09<\/p>\n\n\n\n

\u9694\u79bb\u7ea7\u522b\u64cd\u4f5c\uff1a<\/strong><\/p>\n\n\n\n

\u67e5\u770b\u5f53\u524d\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b<\/strong>
SELECT @@tx_isolation;
\u8bbe\u7f6e\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b<\/strong>
SET [GLOBAL | SESSION] TRANSACTION ISOLATION LEVEL ‘\u9694\u79bb\u7ea7\u522b\u540d\u79f0’;<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\u9694\u79bb\u7ea7\u522b<\/th>\u810f\u8bfb<\/th>\u4e0d\u53ef\u91cd\u590d\u8bfb<\/th>\u5e7b\u8bfb<\/th>\u6027\u80fd<\/th><\/tr><\/thead>
\u8bfb\u672a\u63d0\u4ea4<\/td>\u2705<\/td>\u2705<\/td>\u2705<\/td>\u6700\u9ad8<\/td><\/tr>
\u8bfb\u5df2\u63d0\u4ea4<\/td>\u274c<\/td>\u2705<\/td>\u2705<\/td>\u9ad8<\/td><\/tr>
\u53ef\u91cd\u590d\u8bfb<\/td>\u274c<\/td>\u274c<\/td>\u2705<\/td>\u4e2d<\/td><\/tr>
\u4e32\u884c\u5316<\/td>\u274c<\/td>\u274c<\/td>\u274c<\/td>\u6700\u4f4e<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

MVCC<\/h2>\n\n\n\n

\u5728\u53ef\u91cd\u590d\u8bfb\u3010Repeatable Read\u3011\u4e2d\u8fd8\u662f\u4f1a\u5f15\u8d77\u5e7b\u8bfb\u95ee\u9898\uff0c\u4e8e\u662fmysql\u5c31\u5f15\u5165\u4e86MVCC,\u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236\u662f\u4e00\u79cd\u7528\u6765\u89e3\u51b3 \u8bfb-\u5199\u51b2\u7a81 \u7684\u65e0\u9501\u5e76\u53d1\u63a7\u5236<\/p>\n\n\n\n

\n

1.\u4e3a\u4e8b\u52a1\u5206\u914d\u5355\u5411\u589e\u957f\u7684\u4e8b\u52a1ID\uff0c\u4e3a\u6bcf\u4e2a\u4fee\u6539\u4fdd\u5b58\u4e00\u4e2a\u7248\u672c\uff0c\u7248\u672c\u4e0e\u4e8b\u52a1ID\u5173\u8054\uff0c\u8bfb\u64cd\u4f5c\u53ea\u8bfb\u8be5\u4e8b\u52a1\u5f00\u59cb\u524d\u7684\u6570\u636e\u5e93\u7684\u5feb\u7167\u3002 <\/p>\n\n\n\n

2.\u6240\u4ee5 MVCC \u53ef\u4ee5\u4e3a\u6570\u636e\u5e93\u89e3\u51b3\u4ee5\u4e0b\u95ee\u9898\u5728\u5e76\u53d1\u8bfb\u5199\u6570\u636e\u5e93\u65f6\uff0c\u53ef\u4ee5\u505a\u5230\u5728\u8bfb\u64cd\u4f5c\u65f6\u4e0d\u7528\u963b\u585e\u5199\u64cd\u4f5c\uff0c\u5199\u64cd\u4f5c\u4e5f\u4e0d\u7528\u963b\u585e\u8bfb\u64cd\u4f5c\uff0c\u63d0\u9ad8\u4e86\u6570\u636e\u5e93\u5e76\u53d1\u8bfb\u5199\u7684\u6027\u80fd\u540c\u65f6\u8fd8\u53ef\u4ee5\u89e3\u51b3\u810f\u8bfb\uff0c\u5e7b\u8bfb\uff0c\u4e0d\u53ef\u91cd\u590d\u8bfb\u7b49\u4e8b\u52a1\u9694\u79bb\u95ee\u9898\uff0c\u4f46\u4e0d\u80fd\u89e3\u51b3\u66f4\u65b0\u4e22\u5931\u95ee\u9898<\/p>\n<\/div>\n\n\n\n

\u00a0MVCC \u7684\u5de5\u4f5c\u539f\u7406<\/strong>:<\/p>\n\n\n\n

1. \u9690\u85cf\u5b57\u6bb5<\/strong><\/h3>\n\n\n\n
\n

\u6bcf\u884c\u8bb0\u5f55\u90fd\u6709\u4e09\u4e2a\u9690\u85cf\u5b57\u6bb5\uff1a<\/p>\n\n\n\n

DB_TRX_ID<\/code>\uff1a\u6700\u540e\u4e00\u6b21\u4fee\u6539\u8be5\u884c\u7684\u4e8b\u52a1 ID\u3002<\/p>\n\n\n\n

DB_ROLL_PTR<\/code>\uff1a\u56de\u6eda\u6307\u9488\uff0c\u6307\u5411 undo log \u4e2d\u7684\u65e7\u7248\u672c\u3002<\/p>\n\n\n\n

DB_ROW_ID<\/code>\uff1a\u9690\u542b\u7684\u81ea\u589e ID\uff08\u65e0\u4e3b\u952e\u65f6\u7528\u4e8e\u805a\u7c07\u7d22\u5f15\uff09\u3002<\/p>\n<\/div>\n\n\n\n

\n

2. Undo Log\uff08\u7248\u672c\u94fe\uff09<\/strong><\/h3>\n\n\n\n

\u6bcf\u6b21\u66f4\u65b0\u6570\u636e\u65f6\uff0c\u65e7\u7248\u672c\u88ab\u5199\u5165 undo log<\/strong>\uff0c\u5f62\u6210\u4e00\u6761\u7248\u672c\u94fe<\/strong>\u3002<\/p>\n\n\n\n

\u6700\u65b0\u7248\u672c \u2190\u2192 \u65e7\u7248\u672c \u2190\u2192 \u66f4\u65e7\u7248\u672c \u2190\u2192 ...<\/code><\/p>\n\n\n\n

\"\"<\/figure>\n<\/div>\n\n\n\n

3. Read View\uff08\u4e00\u81f4\u6027\u89c6\u56fe\uff09<\/strong><\/h3>\n\n\n\n
\n

\u6bcf\u4e2a\u4e8b\u52a1\u5728\u542f\u52a8\u65f6\uff08\u6216\u7b2c\u4e00\u6b21\u8bfb\u65f6\uff09\u4f1a\u751f\u6210\u4e00\u4e2a Read View<\/strong>\uff0c\u5305\u542b\uff1a<\/p>\n\n\n\n

\u5f53\u524d\u6d3b\u8dc3\u4e8b\u52a1 ID \u5217\u8868\u3002<\/p>\n\n\n\n

\u6700\u5c0f\u6d3b\u8dc3\u4e8b\u52a1 ID\uff08min_trx_id<\/code>\uff09\u3002<\/p>\n\n\n\n

\u6700\u5927\u4e8b\u52a1 ID\uff08max_trx_id<\/code>\uff09\u3002<\/p>\n\n\n\n

\u521b\u5efa\u8be5 Read View \u7684\u4e8b\u52a1 ID\uff08creator_trx_id<\/code>\uff09\u3002<\/p>\n<\/div>\n\n\n\n

\u53ef\u8bfb\u6027\u89c4\u5219<\/strong>\uff1a<\/p>\n\n\n\n

class ReadView {\n\/\/ \u7701\u7565...\nprivate:\n\/** \u9ad8\u6c34\u4f4d\uff0c\u5927\u4e8e\u7b49\u4e8e\u8fd9\u4e2aID\u7684\u4e8b\u52a1\u5747\u4e0d\u53ef\u89c1*\/\ntrx_id_t m_low_limit_id\u6211\u4eec\u5728\u5b9e\u9645\u8bfb\u53d6\u6570\u636e\u7248\u672c\u94fe\u7684\u65f6\u5019\uff0c\u662f\u80fd\u8bfb\u53d6\u5230\u6bcf\u4e00\u4e2a\u7248\u672c\u5bf9\u5e94\u7684\u4e8b\u52a1ID\u7684\uff0c\u5373\uff1a\u5f53\u524d\u8bb0\u5f55\u7684DB_TRX_ID \u3002\n\u90a3\u4e48\uff0c\u6211\u4eec\u73b0\u5728\u624b\u91cc\u9762\u6709\u7684\u4e1c\u897f\u5c31\u6709\uff0c\u5f53\u524d\u5feb\u7167\u8bfb\u7684 ReadView \u548c \u7248\u672c\u94fe\u4e2d\u7684\u67d0\u4e00\u4e2a\u8bb0\u5f55\u7684\nDB_TRX_ID \u3002\n\u6240\u4ee5\u73b0\u5728\u7684\u95ee\u9898\u5c31\u662f\uff0c\u5f53\u524d\u5feb\u7167\u8bfb\uff0c\u5e94\u4e0d\u5e94\u8be5\u8bfb\u5230\u5f53\u524d\u7248\u672c\u8bb0\u5f55\u3002\u4e00\u5f20\u56fe\uff0c\u89e3\u51b3\u6240\u6709\u95ee\u9898\uff01\n\/** \u4f4e\u6c34\u4f4d\uff1a\u5c0f\u4e8e\u8fd9\u4e2aID\u7684\u4e8b\u52a1\u5747\u53ef\u89c1 *\/\ntrx_id_t m_up_limit_id;\n\/** \u521b\u5efa\u8be5 Read View \u7684\u4e8b\u52a1ID*\/\ntrx_id_t m_creator_trx_id;\n\/** \u521b\u5efa\u89c6\u56fe\u65f6\u7684\u6d3b\u8dc3\u4e8b\u52a1id\u5217\u8868*\/\nids_t m_ids;\n\/** \u914d\u5408purge\uff0c\u6807\u8bc6\u8be5\u89c6\u56fe\u4e0d\u9700\u8981\u5c0f\u4e8em_low_limit_no\u7684UNDO LOG\uff0c\n* \u5982\u679c\u5176\u4ed6\u89c6\u56fe\u4e5f\u4e0d\u9700\u8981\uff0c\u5219\u53ef\u4ee5\u5220\u9664\u5c0f\u4e8em_low_limit_no\u7684UNDO LOG*\/\ntrx_id_t m_low_limit_no;\n\/** \u6807\u8bb0\u89c6\u56fe\u662f\u5426\u88ab\u5173\u95ed*\/\nbool m_closed;\n\/\/ \u7701\u7565...\n};<\/code><\/pre>\n\n\n\n
\u6761\u4ef6<\/th>\u662f\u5426\u53ef\u89c1<\/th><\/tr><\/thead>
\u7248\u672c trx_id < min_trx_id<\/code><\/td>\u2705 \u5df2\u63d0\u4ea4<\/td><\/tr>
\u7248\u672c trx_id > max_trx_id<\/code><\/td>\u274c \u672a\u6765\u4e8b\u52a1<\/td><\/tr>
\u7248\u672c trx_id<\/code> \u5728\u6d3b\u8dc3\u5217\u8868\u4e2d<\/td>\u274c \u672a\u63d0\u4ea4<\/td><\/tr>
\u7248\u672c trx_id == creator_trx_id<\/code><\/td>\u2705 \u81ea\u5df1\u6539\u7684<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\u4e3e\u4f8b\u8bf4\u660e\uff1a<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\u5f53select\u65f6\u5c31\u4f1a\u4fdd\u5b58\u5feb\u7167\uff0c\u6839\u636e\u4e0a\u9762\u7684\u89c4\u5219\u53bb\u67e5\u8be2\u5df2\u63d0\u4ea4\u7684\u4e8b\u52a1\u548c\u672a\u63d0\u4ea4\u7684\u4e8b\u52a1\u3002<\/p>\n\n\n\n
MVCC \u7684\u4f18\u70b9\u4e0e\u9650\u5236<\/strong><\/p>\n\n\n\n
\u4f18\u70b9<\/th>\u9650\u5236<\/th><\/tr><\/thead>
\u8bfb\u4e0d\u963b\u585e\u5199\uff0c\u5199\u4e0d\u963b\u585e\u8bfb<\/td>\u9700\u8981\u989d\u5916\u5b58\u50a8 undo log<\/td><\/tr>
\u9ad8\u5e76\u53d1\u6027\u80fd<\/td>\u957f\u65f6\u95f4\u4e8b\u52a1\u53ef\u80fd\u5bfc\u81f4\u201c\u7248\u672c\u94fe\u201d\u8fc7\u957f\uff0c\u5f71\u54cd\u6027\u80fd<\/td><\/tr>
\u652f\u6301\u4e00\u81f4\u6027\u975e\u9501\u5b9a\u8bfb<\/td>\u4e0d\u652f\u6301\u89e3\u51b3\u6240\u6709\u5e7b\u8bfb\uff08InnoDB \u901a\u8fc7\u95f4\u9699\u9501\u89e3\u51b3\uff09<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\u603b\u7ed3<\/strong>\uff1aMVCC \u662f\u6570\u636e\u5e93\u5b9e\u73b0\u201c\u9ad8\u6548\u5e76\u53d1\u63a7\u5236\u201d\u7684\u6838\u5fc3\u6280\u672f\uff0c\u901a\u8fc7\u4fdd\u5b58\u6570\u636e\u7684\u5386\u53f2\u7248\u672c\uff0c\u8ba9\u8bfb\u5199\u4e92\u4e0d\u963b\u585e\uff0c\u4ece\u800c\u63d0\u5347\u6027\u80fd\u5e76\u4fdd\u8bc1\u4e00\u81f4\u6027\u3002<\/strong><\/p>\n\n\n\n
\u4eca\u5929\u7684\u66f4\u65b0\u5c31\u5230\u8fd9\u91cc\uff0c\u5982\u6709\u9519\u8bef\u6b22\u8fce\u8bc4\u8bba\u533a\u6307\u51fa\uff01\uff01\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
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